Fibrous nitrogen-doped carbon metal mesh composite membranes for water treatment and methods of making the same

Abstract

The application discloses a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, which utilizes a metal mesh as a base film and a metal source, uses amino acids as a nitrogen source and a carbon source, and forms a stable nitrogen-doped carbon layer through a calcination process and uniformly distributes the nitrogen-doped carbon layer on the surface of the metal mesh. The application utilizes abundant amino and carboxyl functional groups in amino acid molecules, forms a stable chemical chelate structure with metal ions of the metal mesh base through coordination bonding, and effectively enhances the interfacial bonding strength between the nitrogen-doped carbon and the metal mesh base film in the carbonization process through the bonding mechanism at the molecular level.

Description

Technical Field

[0001] This invention relates to a composite membrane and its preparation method, specifically to a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment and its preparation method. Background Technology

[0002] With industrialization, water pollution has become increasingly serious, and developing efficient, environmentally friendly, and sustainable water treatment technologies has become an important direction for solving global environmental and resource problems. Among them, membrane separation technology, due to its high efficiency and energy-saving characteristics, has become one of the important means to solve water pollution problems. Traditional membrane materials (such as ceramic membranes, polymer membranes, etc.) have certain limitations in water treatment, such as low mechanical strength, poor flexibility, or insufficient antifouling ability, making it difficult to meet the requirements of high efficiency and durability in practical applications.

[0003] In recent years, nitrogen-doped carbon materials have shown significant advantages in catalysis, adsorption, and energy storage due to their unique electronic structure, high specific surface area, and abundant active sites. For example, Yang et al. prepared a nitrogen-doped carbon catalyst by carbonization using cotton fibers from waste cotton as the carbon source and low-cost urea as the nitrogen source. This catalyst was used to activate persulfate (PMS) to degrade Reactive Blue 19 in wastewater. The results showed that the prepared catalyst achieved a degradation efficiency of 99% for Reactive Blue 19 within 40 minutes, and the active sites (pyridine nitrogen, pyrrole nitrogen, and C=C species) of the nitrogen-doped carbon catalyst played a crucial role in PMS activation. The introduction of nitrogen atoms can regulate the electron distribution of the carbon skeleton, enhance the interaction between the material and pollutants or reactants, and improve adsorption, conductivity, and catalytic activity. However, the preparation methods of nitrogen-doped carbon materials usually employ powder structures, which are difficult to recycle and reuse, and cannot meet the requirements of material continuity and mechanical strength in practical applications.

[0004] Metal meshes possess excellent mechanical properties, high water flux, and recyclability. Furthermore, their surfaces contain abundant metal active sites, allowing for the creation of surface catalytic layers with varying morphologies and properties through chemical and physical modifications. As substrates for the dense growth of other materials, metal meshes are an excellent choice for both metal sources and base films in heterogeneous Fenton-like catalytic membrane systems. Combining metal meshes with nitrogen-doped carbon materials can effectively enhance the overall performance of the materials. However, the smoothness of the metal mesh surface often results in insufficient adhesion of the carbon layer, affecting long-term stability and effectiveness. Therefore, how to combine nitrogen-doped carbon materials with metal meshes for the efficient treatment of pollutants in water remains a pressing technical challenge. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment. By coordinating and bonding the amino / carboxyl groups of amino acids with metal ions, the binding force between the catalyst and the support is enhanced during the carbonization process, and the nitrogen-doped carbon is regulated to form a fibrous structure, thereby achieving efficient removal of organic matter from water by the composite membrane.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment uses the metal mesh as the base membrane and metal source, and amino acids containing nitrogen and carbon elements as the nitrogen source and carbon source. A stable nitrogen-doped carbon layer is formed through a calcination process and is uniformly distributed on the surface of the metal mesh.

[0008] Another aspect of the present invention provides a method for preparing a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, comprising the following steps:

[0009] (1) Cut and pre-treat the metal mesh. The cutting of the metal mesh can be carried out according to the actual application and the shape is not fixed.

[0010] (2) Take the metal mesh obtained in step (1), soak it in an amino acid aqueous solution at a certain temperature, take it out, and put it in an oven to dry;

[0011] (3) Take the dried metal mesh from step (2) and calcine it in a tube furnace under a protective atmosphere to make a fibrous nitrogen-doped carbon metal mesh composite film for water treatment.

[0012] In step (1), the pretreatment of the metal mesh can be divided into acid pretreatment and alkali pretreatment. The acid pretreatment involves placing the cut metal mesh into acetone, isopropanol, ethanol and deionized water in sequence and sonicating for 1 to 30 minutes to remove oil, and then soaking it in HCl aqueous solution for 1 to 60 minutes to remove the oxide layer. The alkali pretreatment involves immersing the cut metal mesh in a mixed solution for 1 to 60 minutes, then taking it out and rinsing it with deionized water. The mixed solution is a mixture of ammonium persulfate, sodium hydroxide and deionized water.

[0013] The concentration of the HCl aqueous solution is 1~10 mol / L; the mass ratio of ammonium persulfate: sodium hydroxide: deionized water in the alkali pretreatment mixed solution is 0.1~1:0.1~5:1~50.

[0014] In step (1), the metal mesh is one of molybdenum mesh, nickel mesh, titanium mesh, copper mesh or stainless steel mesh; in step (2), the amino acid solution is obtained by dissolving amino acids in deionized water; the amino acid is one of D-glutamic acid, L-glutamic acid, L-histidine, L-lysine, L-arginine or L-cysteine.

[0015] In step (2), the solution temperature is 20~95 ℃ and the soaking time is 1~12 h; in step (2), the solution is placed in an oven at 50~120℃ for drying; in step (3), the mass concentration of the amino acid solution is 0.1%~10%.

[0016] In step (3), the calcination temperature is 400~1000 ℃, the heating rate is 1~10 ℃ / min, and the calcination time is 1 h~5 h; the protective atmosphere is nitrogen or argon.

[0017] In step (3), the amino acid solution is an L-histidine solution with a mass concentration of 1%; the calcination temperature in step (3) is 500 ℃, the heating rate is 5 ℃ / min, and the calcination time is 2 h.

[0018] The above describes the application of fibrous nitrogen-doped carbon metal mesh composite membranes used for water treatment in the catalytic degradation of organic pollutants.

[0019] The organic pollutant is one of bisphenol A, methylene blue, or the antibiotic tetracycline.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] This invention utilizes the abundant amino and carboxyl functional groups in amino acid molecules to form a stable chemical chelate structure with metal ions on a metal mesh substrate through coordination bonding. This molecular-level bonding mechanism effectively enhances the interfacial bonding strength between nitrogen-doped carbon and the metal mesh film during carbonization. More importantly, the molecular diversity of amino acids allows for precise control of the surface chemical properties of the material. Their bonding with metal ions on the metal mesh substrate can regulate the formation of a fibrous structure from nitrogen-doped carbon during carbonization. This structure significantly improves the catalytic activity and selectivity of the composite membrane, making it more effective in treating organic pollutants. The introduction of nitrogen-doped carbon also enhances the electron transfer capacity of the composite membrane, improving the efficiency of the catalytic reaction. Furthermore, amino acids, as natural molecules, possess low toxicity and biodegradability, and the modification process is environmentally friendly with no secondary pollution, meeting the requirements of green chemistry and sustainable development. This process combines the advantages of simplicity, high efficiency, and strong structural designability. The resulting fibrous nitrogen-doped carbon metal mesh membrane exhibits excellent degradation effects on new pollutants such as dyes, antibiotics, and bisphenol A through an adsorption-oxidation synergistic mechanism, demonstrating broad application prospects in water treatment. Attached Figure Description

[0022] Figure 1 This is a scanning electron microscope image of an untreated copper mesh with a radius of 2 cm.

[0023] Figure 2This is a scanning electron microscope image of a copper mesh obtained by acid pretreatment in step (2) of Example 1.

[0024] Figure 3 This is a field emission electron microscope (FET) scan of the fibrous nitrogen-doped carbon metal mesh composite film for water treatment prepared in Example 1.

[0025] Figure 4 This is an electron microscope scan image of a copper mesh obtained from the alkali pretreatment in step (2) of Example 2.

[0026] Figure 5 This is a field emission electron microscope (FET) scan of the fibrous nitrogen-doped carbon metal mesh composite film for water treatment prepared in Example 2.

[0027] Figure 6 The removal rate of bisphenol A by a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, prepared using an acid pretreatment method.

[0028] Figure 7 The removal rate of bisphenol A by a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, prepared using an alkaline pretreatment method.

[0029] Figure 8 The removal rate of bisphenol A by the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 3 is shown.

[0030] Figure 9 The removal rate of bisphenol A by the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 4 is shown.

[0031] Figure 10 The removal rate of methylene blue dye by the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 1 is shown.

[0032] Figure 11 The removal rate of the antibiotic tetracycline by the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 1 is shown. Detailed Implementation

[0033] The following detailed description, in conjunction with the accompanying drawings, outlines specific embodiments. However, it should be understood that the scope of protection of this invention is not limited to these specific embodiments. Unless otherwise specified, all raw materials and reagents used in the examples are commercially available.

[0034] Example 1

[0035] A method for preparing a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, comprising the following steps:

[0036] (1) Cut the copper mesh into a circle with a radius of 2 cm. Place the cut copper mesh into acetone, isopropanol, ethanol and deionized water in sequence and sonicate for 15 min to remove oil. Then soak it in 2 mol / L HCl aqueous solution for 30 min to remove the oxide layer.

[0037] (2) Weigh 1 g of L-histidine into a beaker, add 100 g of deionized water, and sonicate until completely dissolved to prepare an amino acid solution with a mass concentration of 1.0 wt% for later use; take the metal mesh obtained after pretreatment in step (1) and immerse it in the prepared amino acid solution, cover it with plastic wrap and place it in a 90 ℃ water bath for 4 h, then take it out and dry it in a 60 ℃ oven.

[0038] (3) Take the metal mesh obtained after drying in step (2) and place it under nitrogen in a tube furnace. Maintain a heating rate of 5℃ / min and calcine at 500℃ for 2 h to obtain a fibrous nitrogen-doped carbon metal mesh composite film for water treatment.

[0039] Example 2

[0040] A method for preparing a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, comprising the following steps:

[0041] (1) Cut the copper mesh into a circle with a radius of 2 cm, immerse the cut copper mesh in the mixed solution for 30 min, take it out and rinse it with deionized water (the mixed solution is obtained by mixing 2.5 g of ammonium persulfate, 10 g of sodium hydroxide and 100 mL of deionized water), and the pretreatment is completed;

[0042] (2) Weigh 1 g of L-histidine into a beaker, add 100 g of deionized water, and sonicate until completely dissolved to prepare an amino acid solution with a mass concentration of 1.0 wt% for later use; take the metal mesh obtained after pretreatment in step (1) and immerse it in the prepared amino acid solution, cover it with plastic wrap and place it in a 90 ℃ water bath for 4 h, then take it out and dry it in a 60 ℃ oven.

[0043] (3) Take the metal mesh obtained after drying in step (2) and place it under nitrogen in a tube furnace. Maintain a heating rate of 5℃ / min and calcine at 500℃ for 2 h to obtain a fibrous nitrogen-doped carbon metal mesh composite film for water treatment.

[0044] Example 3

[0045] In step (2), “L-histidine” is replaced with “D-glutamic acid”, and the rest of the operation is the same as in Example 1, to obtain a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment.

[0046] Example 4

[0047] In step (3), the calcination is carried out at 600℃ for 2 h, and the remaining operations are the same as in Example 1, to obtain a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment.

[0048] Example 5

[0049] Scanning electron microscopy (SEM) images of the metal mesh composite films prepared in Examples 1-2 were acquired using a field emission scanning electron microscope to characterize the microstructure of the films.

[0050] Figure 1 This is a scanning electron microscope image of an untreated copper mesh with a radius of 2 cm. It can be observed that the surface of the untreated copper mesh is smooth and free of impurities.

[0051] Figure 2 The image is a scanning electron microscope image of a copper mesh obtained by acid pretreatment according to step (2) of Example 1. The surface of the copper mesh becomes rough after acid pretreatment, which is beneficial to the subsequent adhesion of nitrogen-doped carbon.

[0052] Figure 3 This is a field emission scanning electron microscope image of the nitrogen-doped carbon metal mesh water treatment membrane obtained by calcination after loading amino acids in step (3) of Example 1. It can be observed that a large number of fibrous nitrogen-doped carbons are attached to the surface of the copper mesh, indicating that the nitrogen-doped carbons with amino acids as nitrogen and carbon sources are successfully loaded and appear fibrous on the surface of the copper mesh, proving the successful preparation of the fibrous nitrogen-doped carbon metal mesh water treatment membrane in this invention.

[0053] Figure 4 The image is a scanning electron microscope image of a copper mesh obtained by alkaline pretreatment in step (2) of Example 2. The surface of the copper mesh becomes rough after alkaline pretreatment, which is beneficial for the subsequent adhesion of nitrogen-doped carbon.

[0054] Figure 5 This is a field emission scanning electron microscope image of the nitrogen-doped carbon metal mesh water treatment membrane obtained by calcination after loading amino acids in step (3) of Example 2. It can be observed that a large number of fibrous nitrogen-doped carbons are attached to the surface of the copper mesh, indicating that both acid-pretreated and alkali-pretreated copper meshes can be successfully used to prepare fibrous nitrogen-doped carbon metal mesh water treatment membranes.

[0055] Application Example 1

[0056] Bisphenol A (BPA) is an organic compound containing a bisphenol group. It is a major material in the production of polycarbonate and epoxy resins, and is widely used in many plastic products as a plasticizer, stabilizer, and antioxidant. my country's "Standards for Drinking Water Quality" (GB 5749—2022) sets the limit for BPA at 0.01 mg / L. Normal human exposure is below this dose. However, BPA in the aquatic environment can cause long-term, low-dose exposure in humans, leading to toxicological effects even at levels far below this limit.

[0057] The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 1 was used to conduct catalytic degradation experiments on simulated bisphenol A wastewater, as follows:

[0058] A piece of nitrogen-doped carbon metal mesh membrane prepared in Example 1 was weighed. The pretreatment of the copper mesh was acid washing. It was added to 100 mL of bisphenol A solution (pH 7.0, 20 mg / L), and 1 mL of oxidant H₂O₂ solution was added. A static catalytic degradation experiment was conducted in a shaker at 40 °C (40 °C, 180 r / min). Samples were taken at regular intervals, quenched with an equal volume of methanol, and filtered through a 0.22 μm mixed cellulose MCE filter to obtain the sample solution. The concentration of bisphenol A solution was calculated using high-performance liquid chromatography. The removal rate of bisphenol A in water during this process was calculated according to the formula. Furthermore, the removal rate of BPA by this composite membrane is as follows: Figure 6 As shown, the nitrogen-doped carbon metal mesh membrane achieved a BPA removal rate of 97.55% within 60 minutes, realizing the efficient removal of organic pollutants.

[0059] Application Example 2

[0060] The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 2 was used to conduct catalytic degradation experiments on simulated bisphenol A wastewater. The method is as follows:

[0061] A piece of nitrogen-doped carbon metal mesh membrane prepared in Example 1 was weighed. The pretreatment of the copper mesh was alkaline washing. It was added to 100 mL of bisphenol A solution (pH 7.0, 20 mg / L), and 1 mL of oxidant H₂O₂ solution was added. A static catalytic degradation experiment was conducted in a shaker at 40 °C (40 °C, 180 r / min). Samples were taken at regular intervals, quenched with an equal volume of methanol, and filtered through a 0.22 μm mixed cellulose MCE filter to obtain the sample solution. The concentration of bisphenol A solution was calculated using high-performance liquid chromatography. The removal rate of bisphenol A in water during this process was calculated according to the formula. Furthermore, the removal rate of BPA by this composite membrane is as follows: Figure 7 As shown, the nitrogen-doped carbon metal mesh membrane achieved a 100% removal rate of BPA within 60 minutes, realizing the complete removal of organic pollutants.

[0062] Application Example 3

[0063] The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 3 was used to conduct catalytic degradation experiments on simulated bisphenol A wastewater. The method is as follows:

[0064] A single fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, prepared in Example 3, was weighed and added to 100 mL of bisphenol A solution (pH 7.0, 20 mg / L). 1 mL of oxidant H₂O₂ solution was added, and the mixture was shaken in a shaker at 40°C (40 °C, 180 r / min) for static catalytic degradation. Samples were taken at regular intervals, quenched with an equal volume of methanol, and filtered through a 0.22 μm mixed cellulose MCE filter to obtain the sample solution. The concentration of the bisphenol A solution was calculated using high-performance liquid chromatography (HPLC). The removal rate of bisphenol A in the water during this process was calculated using the formula. Furthermore, the removal rate of BPA by this composite membrane is as follows: Figure 8 As shown, the fibrous nitrogen-doped carbon metal mesh prepared with D-glutamic acid can also effectively remove bisphenol A (BPA) from water. Within 60 min, the removal rate of BPA by the nitrogen-doped carbon metal mesh is as high as 97.07%.

[0065] Application Example 4

[0066] The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 4 was used to conduct catalytic degradation experiments on simulated bisphenol A wastewater, as follows:

[0067] A single fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, prepared in Example 4, was weighed and added to 100 mL of bisphenol A solution (pH 7.0, 20 mg / L). 1 mL of oxidant H₂O₂ solution was added, and the mixture was shaken in a shaker at 40 °C (180 r / min) for static catalytic degradation. Samples were taken at regular intervals, quenched with an equal volume of methanol, and filtered through a 0.22 μm mixed cellulose MCE filter to obtain the sample solution. The concentration of bisphenol A solution was calculated using high-performance liquid chromatography (HPLC). The removal rate of bisphenol A in water during this process was calculated using the formula. Furthermore, the removal rate of BPA by this composite membrane is as follows: Figure 9 As shown, the fibrous nitrogen-doped carbon metal mesh prepared under calcination conditions at 600℃ can also effectively remove bisphenol A (BPA) from water. Within 60 min, the removal rate of BPA by the nitrogen-doped carbon metal mesh is as high as 96.63%.

[0068] Application Example 5

[0069] Experiments were conducted on the catalytic degradation of simulated methylene blue dye wastewater using a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment.

[0070] Weigh one piece of the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 1, and add it to 100 mL of methylene blue dye solution (pH 7.0, 20 mg / L). Add 1 mL of oxidant H2O2 solution and conduct a static catalytic degradation experiment in a shaker at 40 °C (40 °C, 180 r / min). Samples are taken at regular intervals, quenched with an equal volume of methanol, and filtered through a 0.22 μm mixed cellulose MCE filter to obtain the sample solution. The concentration of the methylene blue dye solution is calculated by measuring with a UV spectrophotometer. The removal rate of methylene blue dye by this nitrogen-doped carbon metal mesh membrane is as follows: Figure 10 As shown: The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 1 can also effectively remove methylene blue dye from water, with a removal rate of 97.80% within 100 min.

[0071] Application Example 6

[0072] Experiments were conducted on the catalytic degradation of simulated tetracycline antibiotic wastewater using a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment.

[0073] One piece of the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 1 was weighed and added to 100 mL of tetracycline antibiotic solution (pH 7.0, 20 mg / L). 1 mL of oxidant H2O2 solution was added, and the mixture was shaken in a shaker at 40 °C (180 r / min) for static catalytic degradation. Samples were taken at regular intervals, quenched with an equal volume of methanol, and filtered through a 0.22 μm mixed cellulose MCE filter to obtain the sample solution. The tetracycline concentration was calculated using a UV spectrophotometer. The removal rate of tetracycline by the nitrogen-doped carbon metal mesh membrane is as follows: Figure 11 As shown: The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared in Example 1 can effectively remove the antibiotic tetracycline from the water. The antibiotic can be completely removed in only 50 minutes, which shows the effectiveness of the composite membrane in removing a variety of organic pollutants.

[0074] Application Example 7

[0075] The copper mesh obtained by acid pretreatment in step (2) of Example 1, the copper mesh obtained by alkali pretreatment in step (2) of Example 2, the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared by acid pretreatment in Example 1, and the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared by alkali pretreatment in Example 2 were used in catalytic degradation experiments on simulated bisphenol A wastewater.

[0076] The copper mesh obtained by acid pretreatment in step (2) of Example 1, the copper mesh obtained by alkali pretreatment in step (2) of Example 2, the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared by acid pretreatment in Example 1, and the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared by alkali pretreatment in Example 2 were respectively added to conical flasks containing 100 mL of bisphenol A solution (20 mg / L), 1 mL of H2O2 was added, and the flasks were placed in a shaker (40 ℃, 180 r / min) for reaction. Samples were taken at certain intervals, quenched with an equal volume of methanol, and filtered through a 0.22 μm mixed cellulose MCE filter to obtain the sample solution. The concentration of bisphenol A solution was calculated by measuring with a high performance liquid chromatography instrument. The bisphenol A degradation results are shown in Table 1. The removal rates of bisphenol A by the acid-pretreated copper mesh membrane and the alkali-pretreated copper mesh membrane were 70.94% and 61.05% respectively after 60 min. However, the removal rates of bisphenol A by the acid-pretreated fibrous nitrogen-doped carbon metal mesh composite membrane and the alkali-pretreated fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment reached as high as 97.55% and 100% after 60 min, respectively. This indicates that the loading of fibrous nitrogen-doped carbon greatly improves the water treatment performance of the metal mesh.

[0077] Table 1: Degradation of Bisphenol A using metal mesh membranes prepared with different pretreatment methods and fibrous nitrogen-doped carbon metal mesh composite membranes for water treatment.

[0078] Group Composite membrane <![CDATA[Dosage of H2O2, mL]]> Bisphenol A concentration (mg / L) Removal rate / % Time / min Example 1, Step (2) Acid-pretreated copper mesh 1 20 70.94 60 Example 2, Step (2) Alkali pretreated copper mesh 1 20 61.05 60 Example 1 Fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment 1 20 97.55 60 Example 2 Fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment 1 20 100 60

[0079] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, characterized in that: Using a metal mesh as the base film and metal source, and amino acids as the nitrogen and carbon sources, stable fibrous nitrogen-doped carbon is formed through a calcination process and uniformly distributed on the surface of the metal mesh.

2. The method for preparing the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment as described in claim 1, characterized in that, The operation includes the following steps: (1) Cut and pre-treat the metal mesh; (2) Take the metal mesh obtained in step (1), soak it in an amino acid aqueous solution at a certain temperature, take it out and dry it; (3) Take the dried metal mesh from step (2) and calcine it under a protective atmosphere to obtain a fibrous nitrogen-doped carbon metal mesh composite film for water treatment.

3. The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment according to claim 2, characterized in that: The pretreatment of the metal mesh in step (1) can be divided into acid pretreatment and alkali pretreatment. The acid pretreatment involves placing the cut metal mesh in acetone, isopropanol, ethanol and deionized water in sequence and sonicating for 1 to 30 minutes to remove oil, and then soaking it in HCl aqueous solution for 1 to 60 minutes to remove the oxide layer. The alkali pretreatment involves immersing the cut metal mesh in a mixed solution for 1 to 60 minutes, then taking it out and rinsing it with water. The mixed solution is a mixture of ammonium persulfate, sodium hydroxide and water.

4. The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment according to claim 3, characterized in that: The concentration of the HCl aqueous solution is 1~10 mol / L; in the mixed solution of alkali pretreatment, the mass ratio of ammonium persulfate: sodium hydroxide: deionized water is 0.1~1:0.1~5:1~50.

5. The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment according to claim 2, characterized in that: The metal mesh in step (1) is one of molybdenum mesh, nickel mesh, titanium mesh, copper mesh or stainless steel mesh; the amino acid solution in step (2) is obtained by dissolving amino acids in water; the amino acid is one of D-glutamic acid, L-glutamic acid, L-histidine, L-lysine, L-arginine or L-cysteine.

6. The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment according to claim 2, characterized in that: The solution temperature in step (2) is 20~95 ℃ and the soaking time is 1~12 h; the drying temperature in step (2) is 50~120℃; the mass concentration of the amino acid solution in step (3) is 0.1%~10%.

7. The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment according to claim 2, characterized in that: The calcination temperature in step (3) is 400~1000 ℃, the heating rate is 1~10 ℃ / min, and the calcination time is 1 h~5 h; the protective atmosphere is nitrogen or argon.

8. The fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment according to claim 2, characterized in that: The amino acid solution mentioned in step (3) is an L-histidine solution with a mass concentration of 1%; the calcination temperature in step (3) is 500 ℃, the heating rate is 5 ℃ / min, and the calcination time is 2 h.

9. The application of the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment as described in claim 1 or the fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment prepared by any of the methods of claims 2-8 in the catalytic degradation of organic pollutants.

10. The application according to claim 9, characterized in that: The organic pollutant is one of bisphenol A, methylene blue, or the antibiotic tetracycline.

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